Fungicidal imidazole oxime derivatives

ABSTRACT

The invention provides imidazole oxime derivatives of the general formula I: ##STR1## or an acid-addition salt or metal salt complex thereof, in which R represents an optionally substituted phenyl group; R 1  represents an optionally substituted alkyl, alkenyl, alkynyl, or aralkyl group; and R 2  represents an optionally substituted alkyl group; processes for their preparation; compositions containing such compounds and their use as fungicides.

This invention relates to certain imidazole oxime derivatives, a processfor their preparation, compositions containing such compounds and theiruse as fungicides.

According to the present invention there is provided a compound of thegeneral formula ##STR2## or an acid-addition salt or metal salt complexthereof, in which R represents an optionally substituted phenyl group;R¹ represents an optionally substituted alkyl, alkenyl, alkynyl oraralkyl group; and R² represents an optionally substituted alkyl group.

When the compounds of this invention contain an alkyl, alkenyl oralkynyl substituent group, this may be linear or branched and maycontain up to 12, preferably up to 6, carbon atoms.

When any of the foregoing substituents are designated as beingoptionally substituted, the substituent groups which are optionallypresent may be any one or more of those customarily employed in thedevelopment of pesticidal compounds, and/or the modification of suchcompounds to influence their structure/activity, persistence,penetration or other property. Specific examples of such substituentsinclude, for example, halogen atoms, nitro, cyano, hydroxyl, alkyl,haloalkyl, alkoxy, haloalkoxy, amino, alkylamino, dialkylamino, formyl,alkoxycarbonyl, carboxyl, alkanoyl, alkylthio, alkylsulphinyl,alkylsulphonyl, carbamoyl and alkylamido groups. When any of theforegoing substituents represents or contains an alkyl substituentgroup, this may be linear or branched and may contain up to 12,preferably up to 6, and especially up to 4, carbon atoms.

It is preferred that R is a phenyl group, substituted by 1 to 3 halogen,especially chlorine, atoms.

Preferably, R¹ represents a C₁₋₁₂ alkyl, particularly a C₁₋₆ alkyl,group, a C₂₋₁₂ alkenyl, particularly a C₂₋₆ alkenyl and especially aC₂₋₄ alkenyl, group, a C₂₋₁₂ alkynyl, particularly a C₂₋₆ alkynyl andespecially a C₂₋₄ alkynyl, group, or a benzyl group, each group beingoptionally substituted by one or more substituents selected from halogenatoms, nitro, cyano, hydroxyl, C₁₋₄ haloalkyl, C₁₋₄ alkoxy, C₁₋₄haloalkoxy, amino, C₁₋₄ alkylamino, di-C₁₋₄ alkylamino, formyl, C₁₋₄alkoxycarbonyl and carboxyl groups.

It is also preferred that R² represents a C₁₋₁₂ alkyl, particularly aC₁₋₆ alkyl, group.

A particularly preferred sub-group of compounds of formula I is that inwhich R represents a fluorophenyl, chlorophenyl, bromophenyl ordichlorophenyl group; R¹ represents a methyl, ethyl, propyl, butyl,pentyl, allyl, propynyl, benzyl, chlorobenzyl, dichlorobenzyl,nitrobenzyl or trifluoromethylbenzyl group; and R² represents a methylgroup.

It should also be appreciated that the compounds of formula I arecapable of existing as different geometric isomers. The invention thusincludes both the individual isomers and mixtures of such isomers.

The present invention also provides a process for the preparation of acompound of formula I as defined above or an acid-addition salt or metalsalt complex thereof which comprises reacting a compound of the generalformula ##STR3## or an acid-addition salt or metal salt complex thereof,in which R and R² are as defined above, with a compound of the generalformula ##STR4## in which R¹ is as defined above, or with anacid-addition salt thereof, and, if desired, reacting the compound offormula I so obtained with a suitable acid or metal salt to form anacid-addition salt or metal salt complex thereof.

If a compound of general formula III is used, it is preferred that thisis generated in situ. If an acid-addition salt of the compound ofgeneral formula III is used, the process is suitably carried out in thepresence of a base, such as sodium acetate.

The process of the invention is conveniently carried out in the presenceof a solvent. Suitable solvents include dimethylformamide, dimethylsulphoxide, ethers, such as tetrahydrofuran, aromatic compounds andalcohols, particularly ethanol. The reaction is suitably carried out ata temperature of 0° C. to 100° C., the preferred reaction temperaturebeing l5° C. to 80° C.

Compounds of formula II and acid-addition salts or metal salt complexesthereof form the subject of our copending application (T55l). They canbe prepared by reacting a compound of the general formula ##STR5## inwhich R is as defined above and R⁴, R⁵ and R⁶, which may be the same ordifferent, represent an alkyl, cycloalkyl, phenyl or benzyl group, witha compound of the general formula ##STR6## in which R² is as definedabove, in the presence of a base, and, if desired, reacting the compoundof formula II so obtained with a suitable acid or metal salt to form anacid-addition salt or metal salt complex thereof. A particularlypreferred compound of formula IV is that in which R⁴, R⁵ and R⁶ allrepresent an ethyl group.

Compounds of formula IV may be prepared according to the methoddescribed by D. Burkhouse and H. Zimmer in Synthesis, 1984, 330.Compounds of formula V may be prepared by the method described by R. G.Jones and K. C. McLaughlin in J. Amer. Chem. Soc., 1949, 71, 244.

Compounds of formula III are known compounds or can be prepared byprocesses analogous to known processes.

The compounds of general formula I have been found to have fungicidalactivity. Accordingly, the invention further provides a fungicidalcomposition which comprises a carrier and, as active ingredient, acompound of formula I or an acid-addition salt or metal salt complexthereof as defined above. A method of making such a composition is alsoprovided which comprises bringing a compound of formula I as definedabove, or an acid-addition salt or metal salt complex thereof, intoassociation with at least one carrier. Such a composition may contain asingle compound or a mixture of several compounds of the presentinvention. It is also envisaged that different isomers or mixtures ofisomers may have different levels or spectra of activity and thuscompositions may comprise individual isomers or mixtures of isomers.

A composition according to the invention preferably contains from 0.5 to95% by weight of active ingredient.

A carrier in a composition according to the invention is any materialwith which the active ingredient is formulated to facilitate applicationto the locus to be treated, which may for example be a plant, seed orsoil, or to facilitate storage, transport or handling. A carrier may bea solid or a liquid, including a material which is normally gaseous butwhich has been compressed to form a liquid, and any of the carriersnormally used in formulating fungicidal compositions may be used.

Suitable solid carriers include natural and synthetic clays andsilicates, for example natural silicas such as diatomaceous earths;magnesium silicates, for example talcs; magnesium aluminium silicates,for example attapulgites and vermiculites; aluminium silicates, forexample kaolinites, montmorillonites and micas; calcium carbonate;calcium sulphate; ammonium sulphate; synthetic hydrated silicon oxidesand synthetic calcium or aluminium silicates; elements, for examplecarbon and sulphur; natural and synthetic resins, for example coumaroneresins, polyvinyl chloride, and styrene polymers and copolymers; solidpolychlorophenols; bitumen; waxes, for example beeswax, paraffin wax,and chlorinated mineral waxes; and solid fertilisers, for examplesuperphosphates.

Suitable liquid carriers include water; alcohols, for exampleisopropanol and glycols; ketones, for example acetone, methyl ethylketone, methyl isobutyl ketone and cyclohexanone; ethers; aromatic oraraliphatic hydrocarbons, for example benzene, toluene and xylene;petroleum fractions, for example, kerosine and light mineral oils;chlorinated hydrocarbons, for example carbon tetrachloride,perchloroethylene and trichloroethane. Mixtures of different liquids areoften suitable.

Fungicidal compositions are often formulated and transported in aconcentrated form which is subsequently diluted by the user beforeapplication. The presence of small amounts of a carrier which is asurface-active agent facilitates this process of dilution. Thuspreferably at least one carrier in a composition according to theinvention is a surface-active agent. For example the composition maycontain at least two carriers, at least one of which is a surface-activeagent.

A surface-active agent may be an emulsifying agent, a dispersing agentor a wetting agent; it may be nonionic or ionic. Examples of suitablesurface-active agents include the sodium or calcium salts of polyacrylicacids and lignin sulphonic acids; the condensation products of fattyacids or aliphatic amines or amides containing at least 12 carbon atomsin the molecule with ethylene oxide and/or propylene oxide; fatty acidesters of glycerol, sorbitol, sucrose or pentaerythritol; condensates ofthese with ethylene oxide and/or propylene oxide; condensation productsof fatty alcohol or alkyl phenols, for example p-octylphenol orp-octylcresol, with ethylene oxide and/or propylene oxide; sulphates orsulphonates of these condensation products; alkali or alkaline earthmetal salts, preferably sodium salts, or sulphuric or sulphonic acidesters containing at least 10 carbon atoms in the molecule, for examplesodium lauryl sulphate, sodium secondary alkyl sulphates, sodium saltsor sulphonated castor oil, and sodium alkylaryl sulphonates such asdodecylbenzene sulphonate; and polymers of ethylene oxide and copolymersof ethylene oxide and propylene oxide.

The compositions of the invention may for example be formulated aswettable powders, dusts, granules, solutions, emulsifiable concentrates,emulsions, suspension concentrates and aerosols. Wettable powdersusually contain 25, 50 or 75% w of active ingredient and usually containin addition to solid inert carrier, 3-10% w of a dispersing agent and,where necessary, 0-10% w of stabiliser(s) and/or other additives such aspenetrants or stickers. Dusts are usually formulated as a dustconcentrate having a similar composition to that of a wettable powderbut without a dispersant, and may be diluted in the field with furthersolid carrier to give a composition usually containing 1/2-10% w ofactive ingredient. Granules are usually prepared to have a size between10 and 100 BS mesh (1.676-0.152 mm), and may be manufactured byagglomeration or impregnation techniques. Generally, granules willcontain 1/2-75% w active ingredient and 0-10% w of additives such asstabilisers, surfactants, slow release modifiers and binding agents. Theso-called "dry flowable powders" consist of relatively small granuleshaving a relatively high concentration of active ingredient.Emulsifiable concentrates usually contain, in addition to a solvent and,when necessary, co-solvent, 1-50% w/v active ingredient, 2-20% w/vemulsifiers and 0-20% w/v of other additives such as stabilisers,penetrants and corrosion inhibitors. Suspension concentrates are usuallycompounded so as to obtain a stable, non-sedimenting flowable productand usually contain 10-75% w active ingredient, 0.5-15% w of dispersingagents, 0.1-10% w of suspending agents such as protective colloids andthixotropic agents, 0-10% w of other additives such as defoamers,corrosion inhibitors, stabilisers, penetrants and stickers, and water oran organic liquid in which the active ingredient is substantiallyinsoluble; certain organic solids or inorganic salts may be presentdissolved in the formulation to assist in preventing sedimentation or asanti-freeze agents for water.

Aqueous dispersions and emulsions, for example compositions obtained bydiluting a wettable powder or a concentrate according to the inventionwith water, also lie within the scope of the invention. The saidemulsions may be of the water-in-oil or of the oil-in-water type, andmay have a thick `mayonnaise` like consistency.

The composition of the invention may also contain other ingredients, forexample other compounds possessing herbicidal, insecticidal orfungicidal properties.

Of particular interest in enhancing the duration of the protectiveactivity of the compounds of this invention is the use of a carrierwhich will provide a slow release of the fungicidal compounds into theenvironment of the plant which is to be protected. Such slow-releaseformulations could, for example, be inserted in the soil adjacent to theroots of a vine plant, or could include an adhesive component enablingthem to be applied directly to the stem of a vine plant.

The invention still further provides the use as a fungicide of acompound of the general formula I as defined above or an acid-additionsalt or metal salt complex thereof or a composition as defined above,and a method for combating fungus at a locus, which comprises treatingthe locus, which may be for example plants subject to or subjected tofungal attack, seeds of such plants or the medium in which such plantsare growing or are to be grown, with such a compound or composition.

The present invention is of wide applicability in the protection of cropplants against fungal attack. Typical crops which may be protectedinclude vines, grain crops such as wheat and barley, rice and tomatoes.The duration of protection is normally dependent on the individualcompound selected, and also a variety of external factors, such asclimate, whose impact is normally mitigated by the use of a suitableformulation.

The invention is further illustrated by the following Examples.

EXAMPLE 1 (i) Preparation of 2,4-dichlorophenyl1-methyl-5-imidazolylmethyl ketone

Butyl lithium (2.2 M, 21 ml) in hexane was added dropwise to a solutionof diethyl (2,4-dichlorophenyl) (ethoxy)methyl phosphonate (7.3° C. 45mmol) in tetrahydrofuran (200 ml) at -78° C., under an atmosphere ofnitrogen. The resulting deep red solution was stirred for 10 minutes andthen treated with N-methyl 5-imidazolecarboxaldehyde (3.75 g, 34 mmol)dissolved in tetrahydrofuran (150 ml). After a further hour at -78° C.,the reaction mixture was allowed to warm to room temperature whereuponit was treated with water and then acidified with concentratedhydrochloric acid (24 ml) and refluxed for 24 hours. After cooling, thetetrahydrofuran was evaporated and the aqueous residue was made basicwith sodium carbonate and then extracted with ethyl acetate (2×300 ml).The combined organic extract was washed with saturated sodium chloridesolution, dried and concentrated. The residue was then chromatographedon silica using 9:1 chloroform: methanol as eluant to give2,4-dichlorophenyl 1-methyl-5-imidazolylmethyl ketone (8.01 g) as awhite solid.

(ii) Preparation of 2,4-dichlorophenyl 1-methyl-5-imidazolylmethylketone 0-4-chlorobenzyloxime (R=2,4-dichlorophenyl; R¹ =4-chlorobenzyl;R² =methyl)

A mixture of the 2,4-dichlorophenyl 1-methyl-5-imidazolylmethyl ketone(0.82g, 3 mmol) obtained in (i), sodium acetate (l.2g, 15 mmol) and0-4-chlorobenzylhydroxylamine hydrochloride (2.9 lg, 15 mmol) wasrefluxed in ethanol (50 ml) for 20 hours. After cooling, water was addedto the reaction mixture and the ethanol was evaporated off under reducedpressure. The aqueous residue was made basic with sodium carbonate andthen extracted with ethyl acetate (2×200 ml). The combined organicextract was then washed with saturated sodium chloride solution, driedand concentrated. Chromatography of the residue on silica using 9:1diethyl ether: methanol as eluant gave, as compound A, the E-isomer(0.53g) and, as compound B, the Z-isomer (0.33g) of 2,4-dichlorophenyl1-methyl-5-imidazolylmethyl ketone 0-4-chlorobenzyloxime as oils.

    ______________________________________                                         Analysis                                                                     ______________________________________                                        E-isomer  Calc:   C: 56.0;   H: 3.9;                                                                             N: 10.3%                                             Found:  C: 54.6;   H: 4.2;                                                                             N: 10.3%                                   Z-isomer  Calc:   C: 56.0;   H: 3.9;                                                                             N: 10.3%                                             Found:  C: 54.6;   H: 4.2;                                                                             N: 10.3%                                   ______________________________________                                    

EXAMPLES 2 TO 26

By processes similar to those described in Example 1 above, furthercompounds according to the invention were prepared as detailed in TableI below. In this table, the compounds are identified by reference toformula I.

                                      TABLE I                                     __________________________________________________________________________    Example                                                                       No.  Isomer                                                                             R          R.sup.1    R.sup.2                                       __________________________________________________________________________     2   E    4-fluorophenyl                                                                           --CH.sub.2 CH.sub.3                                                                      --CH.sub.3                                     3   E/Z  4-fluorophenyl                                                                           benzyl     --CH.sub.3                                     4   E/Z  4-chlorophenyl                                                                           --CH.sub.3 --CH.sub.3                                     5   E/Z  4-chlorophenyl                                                                           --CH.sub.2 CH.sub.3                                                                      --CH.sub.3                                     6   E/Z  4-chlorophenyl                                                                           --CH(CH.sub.3).sub.2                                                                     --CH.sub.3                                     7   E/Z  4-chlorophenyl                                                                           --CH(CH.sub.3)(C.sub.2 H.sub.5)                                                          --CH.sub.3                                     8   E/Z  4-chlorophenyl                                                                           --(CH.sub.2).sub.4 CH.sub.3                                                              --CH.sub.3                                     9   E/Z  4-chlorophenyl                                                                           --CH.sub.2 CH═CH.sub.2                                                               --CH.sub.3                                    10   E/Z  4-chlorophenyl                                                                           --CH.sub.2 C.tbd.CH                                                                      --CH.sub.3                                    11A  E    4-chlorophenyl                                                                           benzyl     --CH.sub.3                                    11B  Z    4-chlorophenyl                                                                           benzyl     --CH.sub.3                                    12   E/Z  4-chlorophenyl                                                                           4-(trifluoro-                                                                            --CH.sub.3                                                         methyl)benzyl                                            13   E/Z  4-chlorophenyl                                                                           2,4-dichlorobenzyl                                                                       --CH.sub.3                                    14A  E    4-bromophenyl                                                                            --CH.sub.2 CH.sub.3                                                                      --CH.sub.3                                    14B  Z    4-bromophenyl                                                                            --CH.sub.2 CH.sub.3                                                                      --CH.sub.3                                    15A  E    4-bromophenyl                                                                            benzyl     --CH.sub.3                                    15B  Z    4-bromophenyl                                                                            benzyl     --CH.sub. 3                                   16A  E    4-bromophenyl                                                                            4-chlorobenzyl                                                                           --CH.sub.3                                    16B  Z    4-bromophenyl                                                                            4-chlorobenzyl                                                                           --CH.sub.3                                    17   E    2,4-dichlorophenyl                                                                       --CH.sub.2 CH.sub.3                                                                      --CH.sub.3                                    18A  E    2,4-dichlorophenyl                                                                       --CH(CH.sub.3).sub.2                                                                     --CH.sub.3                                    18B  Z    2,4-dichlorophenyl                                                                       --CH(CH.sub.3).sub.2                                                                     --CH.sub.3                                    19A  E    2,4-dichlorophenyl                                                                       --(CH.sub.2).sub.3 CH.sub.3                                                              --CH.sub.3                                    19B  Z    2,4-dichlorophenyl                                                                       --(CH.sub.2).sub.3 CH.sub.3                                                              --CH.sub.3                                    20A  E    2,4-dichlorophenyl                                                                       --CH(CH.sub.3)(C.sub.2 H.sub.5)                                                          --CH.sub.3                                    20B  Z    2,4-dichlorophenyl                                                                       --CH(CH.sub.3)(C.sub.2 H.sub.5)                                                          --CH.sub.3                                    21A  E    2,4-dichlorophenyl                                                                       --(CH.sub.2).sub.4 CH.sub.3                                                              --CH.sub.3                                    21B  Z    2,4-dichlorophenyl                                                                       --(CH.sub.2).sub.4 CH.sub.3                                                              --CH.sub.3                                    22A  E    2,4-dichlorophenyl                                                                       --CH(C.sub.2 H.sub.5).sub.2                                                              --CH.sub.3                                    22B  Z    2,4-dichlorophenyl                                                                       --CH(C.sub.2 H.sub.5).sub.2                                                              --CH.sub.3                                    23A  E    2,4-dichlorophenyl                                                                       --CH.sub.2 CH═CH.sub.2                                                               --CH.sub.3                                    23B  Z    2,4-dichlorophenyl                                                                       --CH.sub.2 CH═CH.sub.2                                                               --CH.sub.3                                    24A  E    2,4-dichlorophenyl                                                                       benzyl     --CH.sub.3                                    24B  Z    2,4-dichlorophenyl                                                                       benzyl     --CH.sub.3                                    25A  E    2,4-dichlorophenyl                                                                       4-nitrobenzyl                                                                            --CH.sub.3                                    25B  Z    2,4-dichlorophenyl                                                                       4-nitrobenzyl                                                                            --CH.sub.3                                    26A  E    2,4-dichlorophenyl                                                                       2,4-dichloro-                                                                            --CH.sub.3                                                         benzyl                                                   26B  Z    2,4-dichlorophenyl                                                                       2,4-dichloro-                                                                            --CH.sub.3                                                         benzyl                                                   __________________________________________________________________________     Melting point, high resolution mass spectroscopy and C,H,N analysis data      for the compounds of Examples 2 to 26 is given in Table IA below.        

                                      TABLE IA                                    __________________________________________________________________________                          Analysis %                                              Example                                                                              M. Pt.                                                                            M+         C      H      N                                         No.    °C.                                                                        Calc. Found                                                                              Calc.                                                                            Found                                                                             Calc.                                                                            Found                                                                             Calc.                                                                            Found                                  __________________________________________________________________________     2         261.1277                                                                            261.1281                                                      3         323.1479                                                                            323.1432                                                      4                    59.3                                                                             59.5                                                                              5.3                                                                              5.3 16.0                                                                             15.2                                    5                    60.6                                                                             60.4                                                                              6.1                                                                              5.8 15.2                                                                             15.2                                    6                    61.9                                                                             61.5                                                                              6.2                                                                              6.6 14.4                                                                             14.6                                    7                    62.9                                                                             62.4                                                                              6.6                                                                              6.3 13.8                                                                             14.3                                    8                    63.9                                                                             63.4                                                                              6.9                                                                              7.0 13.2                                                                             13.3                                    9                    62.3                                                                             62.9                                                                              5.5                                                                              6.0 14.5                                                                             15.0                                   10                    62.7                                                                             62.7                                                                              5.0                                                                              5.0 14.6                                                                             14.8                                   11A                   67.3                                                                             67.0                                                                              5.3                                                                              5.6 12.4                                                                             11.8                                   11B                   67.3                                                                             67.0                                                                              5.3                                                                              5.6 12.4                                                                             11.8                                   12                    58.3                                                                             58.2                                                                              4.4                                                                              4.5 10.3                                                                              9.6                                   13                    56.0                                                                             56.2                                                                              3.9                                                                              4.6 10.3                                                                              9.8                                   14A    68             52.2                                                                             51.0                                                                              5.0                                                                              5.0 13.0                                                                             12.8                                   14B                   52.2                                                                             52.5                                                                              5.0                                                                              5.2 13.0                                                                             13.2                                    15A                                                                                      383.06789                                                                          383.0911                                                     15B                                                                           16A    64-65          54.5                                                                             53.3                                                                              4.1                                                                              4.2 10.0                                                                              9.4                                   16B                   54.5                                                                             53.3                                                                              4.1                                                                              4.2 10.0                                                                              9.4                                   17                    53.9                                                                             54.2                                                                              4.8                                                                              5.0 13.5                                                                             13.7                                    18A                                                                                     325.0794                                                                            325.0750                                                     18B                                                                            19A                                                                                                60.2                                                                             59.9                                                                              6.0                                                                              6.4 12.4                                                                             11.6                                   19B                                                                            20A                                                                                     339.0905                                                                            339.0915                                                     20B                                                                            21A                                                                                     353.1061                                                                            353.1087                                                     21B                                                                           22A                   57.8                                                                             57.1                                                                              5.9                                                                              4.9 12.3                                                                             12.3                                   22B                   57.8                                                                             57.1                                                                              5.9                                                                              4.9 12.3                                                                             12.3                                    23A                                                                                     323.0592                                                                            323.0577                                                     23B                                                                            24A                                                                                     373.0794                                                                            373.0748                                                     24B                                                                           25A                   56.7                                                                             56.2                                                                              4.0                                                                              4.6 13.9                                                                             14.3                                   25B                   56.7                                                                             56.2                                                                              4.0                                                                              4.6 13.9                                                                             14.3                                   26A                   51.7                                                                             51.0                                                                              3.4                                                                              3.2  9.5                                                                             10.1                                   26B                   51.7                                                                             51.0                                                                              3.4                                                                              3.2  9.5                                                                             10.1                                   __________________________________________________________________________

EXAMPLE 27

The fungicidal activity of compounds of the invention was investigatedby means of the following tests.

(a) Antisporulant activity against vine downy mildew (Plasmoparaviticola; Pva)

The test s a direct antisporulant one using a foliar spray. The lowersurfaces of leaves of whole vine plants (cv Cabernet Sauvignon) areinoculated by spraying with an aqueous suspension containing 10⁴zoosporangia/ml 2 days prior to treatment with the test compound Theinoculated plants are kept for 24 hours in a high humidity compartment,then 24 hours at glasshouse ambient temperature and humidity. Infectedleaves are sprayed on their lower surfaces with a solution of activematerial in 1:1 water/acetone containing 0.04% "TWEEN 20" (Trade Mark; apolyoxyethylene sorbitan ester surfactant) The spraying is carried outwith a moving track sprayer giving an application rate of 1 kg/ha. Afterspraying, the plants are returned to normal glasshouse conditions for 96hours and are then transferred to the high humidity compartment for 24hours to induce sporulation, prior to assessment. Assessment is based onthe percentage of the leaf area covered by sporulation compared withthat on control leaves. (

b) Direct protectant activity against vine downy mildew (Plasmoparaviticola; Pvp)

The test is a direct protectant one using a foliar spray. The lowersurfaces of leaves of whole vine plants (cv Cabernet Sauvignon) aresprayed with the test compound at a dosage of 1 kilogram of activematerial per hectare using a track sprayer as described under (a), andafter a subsequent 24 hours under normal glasshouse conditions the lowersurfaces of the leaves are inoculated by spraying with an aqueoussolution containing 10⁴ zoosporangia/ml. The inoculated plants are keptfor 24 hours in a high humidity compartment, 5 days under normalglasshouse conditions and then returned for a further 24 hours to highhumidity. Assessment is based on the percentage of leaf area covered bysporulation compared with that on control leaves.

(c) Direct protectant activity against vine grey mould (Botrytiscinerea; BcP)

The test is a direct protectant one using a foliar spray. The lowersurfaces of detached vine leaves (cv Cabernet Sauvignon) are sprayedwith the test compound at a dosage of 1 kg/ha using a track sprayer asin (a). 24 hours after spraying the leaves are inoculated with dropletsof aqueous suspension containing 10⁵ conidia/ml. After a further 5 daysin high humidity the percentage of leaf area covered by disease isassessed.

(d) Activity against wheat leafspot (Leptosphaeria nodorum; Ln.)

The test is a direct therapeutic one, using a foliar spray. Leaves ofwheat plants (cv Mardler), at the single leaf stage, are inoculated byspraying with an aqueous suspension containing 1×10⁶ spores/ml. Theinoculated plants are kept for 24 hours in a high humidity compartmentprior to treatment. The plants are sprayed with a solution of the testcompound at a dosage of 1 kilogram of active material per hectare usinga track sprayer as described under (a). After drying, the plants arekept for 6-8 days at 20°-25° C. and moderate humidity, followed byassessment. Assessment is based on the density of lesions per leafcompared with that on leaves of control plants.

(e) Activity against barley powdery mildew (Erysiphe graminis f.sp.hordei; Eg)

The test is a direct therapeutic one, using a foliar spray. Leaves ofbarley seedlings, (cv. Golden Promise) are inoculated by dusting withmildew conidia one day prior to treatment with the test compound. Theinoculated plants are kept overnight at glasshouse ambient temperatureand humidity prior to treatment. The plants are sprayed with the testcompound at a dosage of 1 kilogram of active material per hectare usinga track sprayer as described under (a). After drying, plants arereturned to a compartment at 20°-25° C. and moderate humidity for up to7 days, followed by assessment. Assessment is based on the percentage ofleaf area covered by sporulation compared with that on leaves of controlplants.

(f) Activity against wheat brown rust (Puccinia recondita; Pr)

The test is a direct protectant one using a foliar spray. Wheatseedlings (cv Brigand) are grown to the 1-11/2 leaf stage. The plantsare then sprayed with the test compound at a dosage of 1 kg/ha using atrack sprayer as described under (a). Test compounds are applied assolutions or suspensions in a mixture of acetone and water (50:50 v/v)containing 0.04% surfactant ("TWEEN 20"--Trade Mark).

18-24 hours after treatment, the seedlings are inoculated by sprayingthe plants from all sides with an aqueous spore suspension containingabout 10⁵ spores/ml. For 18 hours after inoculation, the plants are keptin high humidity conditions at a temperature of 20-22° C. Thereafter,the plants are kept in ambient glasshouse conditions, that is, inmoderate relative humidity and at a temperature of 20° C.

The disease is assessed 10 days after inoculation on the basis of thepercentage of the plant covered by sporulating pustules compared withthat on the control plants.

(g) Activity against rice leaf blast (Pyricularia oryzae Po)

The test is a direct therapeutic one using a foliar spray. The leaves ofrice seedlings (about 30 seedlings per pot) are sprayed with an aqueoussuspension containing 10⁵ spores/ml 20-24 hours prior to treatment withthe test compound. The inoculated plants are kept overnight in highhumidity and then allowed to dry before spraying with the test compoundat a dosage of 1 kilogram of active material per hectare using a tracksprayer as described under (a). After treatment the plants are kept in arice compartment at 25-30° C. and high humidity. Assessments are made4-5 days after treatment and are based on the density of necroticlesions per leaf when compared with control plants.

(h) Activity against tomato early bliqht (Alternaria solani; As)

This test measures the contact prophylactic activity of test compoundsapplied as a foliar spray.

Tomato seedlings (cv Outdoor Girl) are grown to the stage at which thesecond true leaf is expanded. The plants are treated using a tracksprayer as described under (a). Test compounds are applied as solutionsor suspensions in a mixture of acetone and water (50:50 v/v) containing0.04% surfactant ("TWEEN 20"--Trade Mark).

One day after treatment the seedlings are inoculated by spraying theleaf upper surfaces with a suspension of A. solani conidia containing10⁴ spores/ml. For 3 days after inoculation plants are kept moist in aglasshouse compartment at or near 100% RH and 21° C. Thereafter plantsare kept under humid, but not saturated, conditions. Disease is assessed7 days after inoculation, based on the density and spread of lesions.

(i) Activity against wheat eyespot in-vitro (Pseudocercosporellaherpotrichoides; PhI)

This test measures the in vitro activity of compounds against the funguscausing wheat eyespot.

The test compound is dissolved or suspended in acetone and is added tomolten half strength Potato Dextrose Agar to give a final concentrationof 100 ppm compound and 3.5% acetone. After the agar has set, plates areinoculated with 6 mm diameter plugs of agar/mycelium taken from a 14 dayold culture of P. herpotrichoides.

Plates are incubated at 20° C. for 12 days and radial growth from theinoculation plug is measured.

(j) Activity against Fusarium in-vitro (Fusarium species; FsI)

This test measures the in vitro activity of compounds against a speciesof Fusarium that causes stem and root rots.

Compound is dissolved or suspended in acetone and added to molten halfstrength Potato Dextrose Agar to give a final concentration of 100 ppmcompound and 3.5% acetone. After the agar has set, plates are inoculatedwith 6 mm diameter plugs of agar and mycelium taken from a 7 day oldculture of Fusarium sp..

Plates are incubated at 20° C. for 5 days and radial growth from theplug is measured.

The extent of disease control in all the above tests is expressed as arating compared with either an untreated control or adiluent-sprayed-control, according to the criteria:

0=less than 50% disease control

1=about 50-80% disease control

2=greater than 80% disease control

The results of these tests are set out in Table II below:

                  TABLE II                                                        ______________________________________                                        Compound                                                                      Example Fungicidal Activity                                                   No.     Pva    Pvp    Bcp  Ln  Eg  Pr  Po  As  PhI  FsI                       ______________________________________                                         1A            2      1    2   2   2   1   2   2    2                          1B     1      2      2        2   1   1   1   1    2                          2                             2               2                               3             1           1   2   1           2    2                          4                             2           1   2                               5                             2               2                               6                             2               2    1                          7                             2   1       1   2    2                          8             2           2   2               1    2                          9                             2               2    1                         10             1               2               2    1                         11A            1               2   1       1        2                         11B            1      1        2       1   1   2    2                         12             2               2   1   1       1    2                         13             1      2        2               1    2                         14A            2               2           1   2                              14B            1               2   1       1   2    1                         15A            2      1        2   1       1   1    1                         15B            2           1   2   1           1    2                         16A     1      2      2        2   1       2   2    2                         16B            2               2   2       1   1    1                         17             2               2   2   1   2   2    2                         18A                        2   2   1       1   2    1                         18B            1           1   2   1       1   2    1                         19A            1      1    1   2   2   1   1   2    2                         19B            1               2   1       1   2    2                         20A            2      1    2   2   2       2   2    2                         20B            2      1    2   2   2   1   2   2    2                         21A                   2    2   2   2   2   2   2    2                         21B                   1        2   2   2       2    2                         22A                   2        2   1       2   2    2                         22B            2           1   2   1           2    2                         23A            2           2   2   2   2   2   2    2                         23B            2           1   2   1   1   2   2    2                         24A            2      2        2   2       2   2    2                         24B            2      1    1   2               2    2                         25A            2      2        2   2       2   2    2                         25B            2               1   1           1    1                         26A            2               2   2   1   2   2    2                         26B            2      1        2   1       2   2    2                         ______________________________________                                    

We claim:
 1. A fungicidal composition comprising a carrier and, asactive ingredient, a fungicidally-effective amount of a compound of theformula: ##STR7## or an acid-addition salt or metal salt complexthereof, wherein R represents an optionally substituted phenyl group;R¹represents an optionally substituted alkyl, alkenyl, alkynyl or aralkylgroup; and R² represents an optionally substituted alkyl group.
 2. Acomposition according to claim 1 wherein R represents a phenyl groupoptionally substituted by one or more substituents selected from halogenatoms, nitro, cyano, hydroxyl, alkyl, haloalkyl, alkoxy, haloalkoxy,amino, alkylamino, dialkylamino, formyl, alkoxycarbonyl, carboxyl,alkanoyl, alkylthio, alkylsulphinyl, alkylsulphonyl, carbamoyl andalkylamido groups.
 3. A composition according to claim 1 wherein Rrepresents a phenyl group substituted by 1 to 3 carbon atoms.
 4. Acomposition according to claim 3 wherein the halogen atoms are chlorineatoms.
 5. A composition according to claim 1 wherein R¹ represents aC₁₋₆ alkyl group, a C₂₋₆ alkenyl group, A C₂₋₆ alkynyl group or a benzylgroup, each group being optionally substituted by one or moresubstituents selected from halogen atoms, nitro, cyano, hydroxyl, C₁₋₄haloalkyl, C₁₋₄ alkoxy, C₁₋₄ haloalkoxy, amino, C₁₋₄ alkylamino, di-C₁₋₄alkylamino, formyl, C₁₋₄ alkoxycarbonyl and carboxyl groups.
 6. Acomposition according to claim 2 wherein R¹ represents a C₁₋₆ alkylgroup, A C₂₋₆ alkenyl group, A C₂₋₆ alkynyl group or a benzyl group,each group being optionally substituted by one or more substituentsselected from halogen atoms, nitro, cyano, hydroxyl, C₁₋₄ haloalkyl,C₁₋₄ alkoxy, C₁₋₄ haloalkoxy, amino, C₁₋₄ alkylamino, di-C₁₋₄alkylamino, formyl, C₁₋₄ alkoxycarbonyl and carboxyl groups.
 7. Acomposition according to claim 1 wherein R² represents a C₁₋₆ alkylgroup.
 8. A composition according to claim 2 wherein R² represents aC₁₋₆ alkyl group.
 9. A composition according to claim 1, wherein Rrepresents a fluorophenyl, chlorophenyl, bromophenyl, or dichlorophenylgroup, and R¹ represents a methyl, ethyl, propyl, butyl, pentyl, allyl,propynyl, benzyl, chlorobenzyl, dichlorobenzyl, nitrobenzyl ortrifluoromethylbenzyl group, and R² represents a methyl group.
 10. Acomposition according to claim 1 comprising at least two carriers, atleast one of which is a surface active agent.
 11. A method of combatingfungus at a locus, which method comprises treating the locus with afungically effective amount of the composition of claim
 1. 12. Themethod of claim 11, wherein said locus comprises plants subject to orsubjected to fungal attack, seeds of such plants, or the medium in whichthe plants are growing or are to be grown.